Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41J—TARGETS; TARGET RANGES; BULLET CATCHERS
  • F41J5/00—Target indicating systems; Target-hit or score detecting systems
  • F41J5/06—Acoustic hit-indicating systems, i.e. detecting of shock waves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41J—TARGETS; TARGET RANGES; BULLET CATCHERS
  • F41J5/00—Target indicating systems; Target-hit or score detecting systems
  • F41J5/04—Electric hit-indicating systems; Detecting hits by actuation of electric contacts or switches
  • F41J5/056—Switch actuation by hit-generated mechanical vibration of the target body, e.g. using shock or vibration transducers
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
  • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
  • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
  • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
  • G06F3/0414—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using force sensing means to determine a position
  • G06F3/04144—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using force sensing means to determine a position using an array of force sensing means

Definitions

• the present invention relates to a device for locating an impact against an interactive surface, by analyzing differences in the propagation time of progressive mechanical waves. BACKGROUND OF THE INVENTION propagating from the impact. It also relates to a method implemented by this device and a corresponding computer program.
• Interactive surface means a two-dimensional or three-dimensional surface, capable of changing its shape in the sense of the static and dynamic elasticity of the materials when subjected to an impact such as a touch, a contact force, a mechanical impulse or else a shock, thereby allowing the propagation of progressive mechanical waves detectable using transducers, including surface acoustic waves, from the impact site.
• the surface deformation can be submillimetric not visible to the naked eye. Plastic, glass or metal surfaces are suitable.
• Each of the known interactive surface objects comprises an impact location device using one or more detection techniques.
• a strong trend towards reducing manufacturing cost and reducing clutter is to retain only the simplest technologies using a limited number of sensors.
• the invention thus relates more precisely to a localization device implementing a technology for detecting the propagation of progressive mechanical waves in an interactive surface, in particular using detectors of the piezoelectric transducer type.
• a first solution is disclosed in US Pat. No. 7,345,677 B2. It is based on a recognition of the position of an impact by learning.
• the method implemented operates a cross correlation between at least one measured acoustic signal from the detection of an acoustic wave generated by an impact on the interactive surface of the object and a reference set called "set of signatures" consisting of responses prerecorded impulse acoustic, each relating to a predefined position that one wishes to associate with a function and recognize when an impact is carried on this position.
• a second solution for example disclosed in US Pat. No. 8,330,744 B2, consists in measuring the perturbation of an impact on the propagation of progressive mechanical waves emitted regularly in the interactive surface independently of this impact.
• This solution is known to be more precise and reliable than the previous one, especially for qualifying or monitoring the impact, but it is also based on recognition of the position of an impact by learning.
• a third, older solution is based on the measurement of a transit time difference of a wave packet generated by an impact to a plurality of piezoelectric detectors and on the deterministic calculation, using a pre-established mathematical formula, the position of a source emitting the wave packet.
• this solution requires an impact location device comprising:
• transducers arranged and distributed against the interactive surface, designed to capture progressive mechanical waves propagating in the interactive surface and transforming them into electrical signals
• an electronic central unit connected to the transducers for receiving their electrical signals, programmed to locate the impact in the interactive surface by analyzing the propagation time differences of the progressive mechanical waves resulting from the impact towards the transducers on the basis of the impact detection instants identified in the received electrical signals.
• a device for locating an impact against an interactive surface capable of propagating progressive mechanical waves from the impact comprising:
• M a set of M transducers arranged and distributed against the interactive surface, M> 4, designed to capture the progressive mechanical waves propagating in the interactive surface and transforming them into electrical signals, and
• an electronic central unit connected to the transducers for receiving their electrical signals, programmed to locate the impact in the interactive surface by analyzing the propagation time differences of the progressive mechanical waves resulting from the impact towards the transducers on the basis of the impact detection instants identified in the electrical signals received,
• the electronic central unit is programmed to:
• the trick of the present invention is to vary the N transducers whose signals will ultimately be exploited for a location according to the position of the impact: these are the N transducers closest to the impact.
• the M transducers are electrically connected to each other in several disjoint groups themselves electrically connected to the electronic central unit,
• At least three additional transducers are arranged and distributed against the interactive surface, designed to capture the progressive mechanical waves propagating in the interactive surface and transform them into electrical signals transmitted independently to the electronic central unit, and
• the electronic central unit is programmed to pre-locate the impact in the interactive surface on the basis of the electrical signals received from the additional transducers and to select the subset of N transducers on the basis of this pre-location.
• the M transducers are electrically connected to each other in four disjoint groups themselves electrically connected to the electronic central unit, so that any four adjacent transducers of the same elementary cell of the transducer array always belong to the four groups respectively. disjointed, and
• the M transducers are electrically connected to each other in nine disjoint groups themselves electrically connected to the electronic central unit, such that nine adjacent transducers forming four adjacent elementary cells having the same central common transducer of the matrix of transducers belong to always to the nine disjoint groups respectively, and
• the M transducers are electrically connected together in three disjoint groups themselves electrically connected to the electronic central unit, and
• the M transducers are connected electrically to each other in six disjoint groups themselves electrically connected to the electronic central unit, such that any three adjacent transducers of the same triangular elementary cell of the transducer array always belong to three disjointed groups, and
• the impact location comprising the following steps:
• a computer program downloadable from a communication network and / or recorded on a computer readable medium and / or executable by a processor, comprising instructions for performing the steps of a localization method of impact according to the invention, when said program is executed on a computer.
• FIG. 1 schematically represents the general structure of an impact locating device according to a first variant of a first embodiment of the invention
• FIG. 2 illustrates the successive steps of an impact locating method according to one embodiment of the invention
• FIGS. 3 and 4 show schematically and partially two other variants of the first embodiment of an impact locating device according to the invention.
• FIG. 5 to 7 show schematically and partially three variants of an impact locating device according to a second embodiment of the invention.
• the installation shown diagrammatically in FIG. 1 comprises a rectangular interactive surface 10, able to propagate progressive mechanical waves from an impact P, and a device for locating any impact. against this interactive surface 10.
• the latter is for example a screen impactile polycarbonate or other material adapted on which is projected, either from the front or from the rear using a rear projection sheet, an image or a video, for example using a projector.
• the locating device comprises:
• a set of M transducers for example piezoelectric sensors, arranged and distributed against the interactive surface 10, with
• M> 4 designed to capture the progressive mechanical waves propagating in the interactive surface 10 and transforming them into electrical signals
• an electronic central unit 12 connected to the M transducers to receive their electrical signals, programmed to locate the impact P in the interactive surface 10 by analyzing differences in the propagation time of the progressive mechanical waves resulting from the impact P towards the M transducers based on P impact detection instants identified in the received electrical signals.
• the interactive surface 10 is any, not necessarily rectangular.
• the number of transducers is also arbitrary, at least equal to four to allow an implementation of the invention. They are advantageously arranged against the rear face of the interactive surface 10 so as not to interfere with an image or video possibly projected on its front face.
• the M transducers are distributed in a regular two-dimensional manner in a matrix of transducers against the interactive surface 10.
• the electronic central unit 12 more precisely comprises an interface 14 for receiving the thirty-six electrical signals supplied independently by each of the thirty-six transducers T 1, T, j , T 6 , 6 .
• This interface 14 may include an analog amplifier.
• the electronic central unit 12 furthermore comprises a module 16 for identifying moments of detection of the impact P in the electrical signals received.
• This module will not be detailed, knowing that such identification is well known to those skilled in the art, as for example taught in US 6,933,930 B2 or US 6,367,800 B1. It can be analog and / or digital, so at least partially programmed.
• the moments of detection of the impact P can not be identified in all the signals received, in particular in those received from the transducers. further away because they are too weak. But in the context of the present invention, this apparent problem is cleverly solved from the moment when these instants can be identified in at least N nearest transducers, as will now be explained.
• the electronic central unit 12 in fact comprises a selector 18 designed and / or programmed to select, among the M transducers, a subset of N transducers, with 3 ⁇ N ⁇ M, whose electrical signals comprise chronologically the first N instants identified impact detection. Given the exploited propagation properties, these N selected electrical signals come from the N transducers closest to the impact P. N is greater than or equal to 3 because it is theoretically the necessary and sufficient number of transducers to be able to determine a location the impact P in the interactive surface 10 according to the teaching of US 6,933,930 B2 or US 6,367,800 B1.
• N 4, 6 or 9, depending on whether the impact P is located between four adjacent transducers forming an elementary cell ⁇ T, j, ⁇ ,, ] +1 , T i + 1 j , T i + 1 j + 1 ⁇ of the matrix ( ⁇ ⁇ ) (this is for example the case of the illustrated impact P which lies between the transducers T 3 , T 3 2 , T 4
• the redundancy of the identified impact detection instants is then exploited to optimize the estimation of the location of the impact P by maximum likelihood, for example.
• the selector 18 may be analog and / or digital, so at least partially programmed.
• the electronic central unit 12 finally comprises a computer 20 programmed to calculate an estimate of the location of the impact P using the instants of impact detection identified in the N selected signals and locations of disposition of the N corresponding transducers. in the interactive surface 10.
• the operation of this calculator 20 will not be detailed, knowing that such an estimate is well known to those skilled in the art, as for example taught in US 6,933,930 B2 or US 6,367,800 B1.
• the various programmed elements mentioned above in the identification module 16, the selector 18 and the computer 20 can form only one, the distinction being purely functional. They may be in the form of one or more microprocessors programmed to perform a number of functions that can be implemented using computer programs, that is to say in the form of a device. computer science.
• an impact P generates progressive mechanical waves intended to propagate in all directions in the interactive surface 10.
• a step 102 the thirty-six transducers Tu, T, T ,, 6,6 capture these progressive mechanical waves and convert them into electrical signals.
• the identification module 16 identifies moments of impact detection in at least a portion of the electrical signals received by the electronic central unit 12. Some of the signals may be too weak for that such an identification can be made, but this is of no importance from the moment at least N times of detection of impact are identified in at least N received electrical signals.
• the computer 20 determines, as previously indicated, the location of the impact P, for example in Cartesian coordinates in the interactive surface 10, on the basis of the N moments of detection of the impact P identified. in the N electrical signals received and selected and respective locations of the N corresponding transducers. This calculation can include the optimization of a likelihood criterion, especially when several adjacent elementary cells are solicited. The method is then ready for the detection of a new impact (return to step 100).
• the calculation step 108 could be executed before the selection step 106.
• Each elementary cell ⁇ T, j , T iJ + 1 , T i + 1 J , T i + 1 J + 1 ⁇ of four transducers neighbors can be independently considered by the electronic central unit 12 during step 108 to produce, using the calculator 20, an impact location estimate using the impact detection instants identified in FIG. this elementary cell and locations of its four transducers.
• the computer 20 can also be configured to measure an impact energy P in addition to its location.
• the good distance between two adjacent transducers in line or column of the matrix of transducers is to be determined so that the spatial width of the pulse is well below this distance, but so that the attenuation is not too strong either on this distance.
• This compromise to find is within the reach of the skilled person.
• the transducers can be advantageously spaced 50 cm +/- 10% in rows and columns. It is thus possible to increase the interactive surface size 10 at will, to present an image wall (s) by multiplying the transducers, without increasing the complexity of the location of impacts.
• a disadvantage of the implementation variant of the embodiment of FIG. 1 is the complexity of the wiring since, for a matrix of thirty-six transducers, thirty-six independent connections to the electronic central unit 12 are required. A simplification of the wiring can therefore be proposed in a second variant of implementation illustrated in FIG.
• the thirty-six transducers T ⁇ , T, j , ..., T 66 are electrically connected to each other in several disjoint groups themselves electrically connected to the electronic central unit 12.
• a first group Gi of nine transducers connected to each other relate to the transducers identified by a reference T 1 + 2U + 2j in the matrix of transducers, where i and j are positive or zero integer indices.
• a second group G 2 of nine transducers connected to each other concerns the transducers identified by a reference T 1 + 2i, 2 + 2j in the matrix of transducers.
• a third group G 3 of nine transducers connected to each other concerns the transducers identified by a reference T 2 + 2U + 2j in the matrix of transducers.
• a fourth group G 4 of nine transducers connected to each other concerns the transducers identified by a reference T 2 + 2i, 2 + 2j in the matrix of transducers.
• all the transducers of the matrix ( ⁇ ⁇ ) are connected to one of these four groups so that only four electrical signals arrive at the interface 14 of the electronic central unit 12. It is noted that these connections are made so that any four adjacent transducers of the same elementary cell ⁇ T,,, , Ti, j + 1, T j i + 1 T i + 1 j + 1 ⁇ of the matrix (T,,) transducers always belong respectively to four disjoint groups G 1; G 2 , G 3 and G 4 .
• At least three additional transducers are arranged and distributed against the interactive surface 10, also designed to pick up the progressive mechanical waves propagating in the interactive surface 10 and transform them into electrical signals transmitted independently to the electronic central unit. 12.
• T A , T B , T c and T D there are four, T A , T B , T c and T D , providing four different electrical signals S A , S B , S c , S D at the same time.
• electronic central unit 12. are advantageously positioned on the diagonals of the interactive surface 10 and in places minimizing the distance of the possible location of imp act furthest away. They do not need to provide a very precise measurement.
• N 4, 6 or 9 times of detection of impacts identified in the signals provided by groups G 1; G 2 , G 3 , G 4 are then assigned to the transducers thus selected for the execution of the location calculation carried out by the computer 20 during step 108.
• a disadvantage of the implementation variant of FIG. 3 appears when the impact P is situated in the vicinity of a row or column of the matrix (T, j ) between two neighboring transducers.
• there are at least two other transducers approximately equidistant from the point of impact P which are taken into account in the selection of step 106 and which belong to the same group d, G 2 , G 3 or G 4 .
• Their two moments of impact detection are then combined into one that results from a superposition of two electrical signals close enough for their pulses to add up.
• This addition of non-differentiable signals generates an error in the identification of the moment of detection of impact and therefore in the location of the step 1 08.
• This error remains nevertheless weak and quite acceptable in a number of applications for which a high accuracy is not wanted.
• an adaptation of the wiring can be proposed in a third variant of implementation illustrated in FIG.
• the thirty-six transducers T ⁇ , T, j, ..., T 6 6 are electrically connected to each other in several disjoint groups themselves electrically connected to the electronic central unit 1 2.
• a first group G of four transducers connected to each other concerns the transducers identified by a reference T 1 + 3U + 3j in the matrix of transducers, where i and j are positive or zero integer indices.
• a second group G ' 2 of four transducers connected to each other concerns the transducers identified by a reference T 1 + 3i, 2 + 3j in the matrix of transducers.
• a third group G ' 3 of four transducers connected to each other relates to the transducers identified by a reference T 1 + 3i, 3 + 3j in the matrix of transducers.
• a fourth group G ' 4 of four transducers connected to each other concerns the transducers identified by a reference T 2 + 3 i, i + 3j in the matrix of transducers.
• a fifth group G ' 5 of four transducers connected to each other relates to the transducers identified by a reference T 2 + 3i , 2 + 3j in the matrix of transducers.
• a sixth group G ' 6 of four transducers connected to each other relates to the transducers identified by a reference T 2 + 3i , 3 + 3 j in the matrix of transducers.
• a seventh group G ' 7 of four transducers connected to each other concerns the transducers identified by a reference T 3 + 3U + 3j in the matrix of transducers.
• An eighth group G ' 8 of four transducers connected to each other relates to the transducers identified by a reference T 3 + 3i 2 + 3j in the matrix of transducers.
• a ninth group G ' 9 of four transducers connected to each other relates to the transducers identified by a reference T 3 + 3i 3 + 3j in the matrix of transducers.
• transducers T A , T B , T c and T D are arranged and distributed against the interactive surface 10, also designed to capture the progressive mechanical waves propagating in the interactive surface 10 and transforming them into electrical signals S A , S B , S c , S D transmitted independently to the electronic central unit 12. They are advantageously positioned on the diagonals of the interactive surface 10 and in places minimizing the distance from the farthest possible impact location. They do not need as before to provide a very precise measurement.
• the N 4, 6 or 9 moments of detection of impacts identified in the signals provided by the groups d, G ' 2 , G' 3 , G ' 4 , G' 5 , G ' 6 , G' 7 , G ' 8 , G ' 9 are then assigned to the transducers thus selected for performing the location calculation performed by the computer 20 during step 108.
• the M transducers can be distributed in a two-dimensional regular manner in staggered rows against the surface
• N 3, 4 or 7 transducers
• a disadvantage of this first variant of implementation of the second embodiment is the complexity of the wiring since, as in the variant of Figure 1, each transducer independently transmits its electrical signal to the electronic central unit 12.
• a simplification of the wiring can therefore be proposed in a second variant of implementation of the second embodiment illustrated in FIG.
• the M transducers are electrically connected to each other in several disjoint groups themselves electrically connected to the electronic central unit 12. For example, all the transducers of the lines and L 3 illustrated in FIG. 6 are connected together in each other. a first group Gi while the transducers of the line L 2 , staggered with respect to and 1_3, are alternately connected to a second group G 2 and a third group G 3 . As in the second variant of FIG.
• At least three additional transducers are arranged and distributed against the interactive surface 10, also designed to pick up progressive mechanical waves propagating in the interactive surface 10 and transforming them into electrical signals transmitted independently to the electronic central unit 12 for the purpose of a pre-location for the selection step 108.
• T A , T b and T C there are some three, T A , T b and T C , providing three different electrical signals S A , S B , S c to the electronic central unit 12.
• a disadvantage of this second implementation variant of the second embodiment is the same as in the second implementation variant of the first embodiment of FIG. 3 when the impact P is close to an edge (ie a segment between any two adjacent transducers) of the staggered arrangement. If necessary, an adaptation of the wiring may be proposed in a third implementation variant of the second embodiment illustrated in FIG. 7.
• the M transducers are electrically connected to each other in several disjoint groups themselves electrically connected to the electronic central unit 12.
• the transducers of the line are alternately connected to a first group G'i and to a second one.
• second group G ' 2 the transducers of the line L 2 are alternatively connected to a third group G ' 3 and a fourth group G' 4
• the transducers of the line L 3 are alternately connected to a fifth group G ' 5 and a sixth group G' 6 .
• three additional transducers T A , T B and T c are arranged and distributed against the interactive surface 10, also designed to pick up progressive mechanical waves. propagating in the interactive surface 10 and converting them into electrical signals S A , S B , S c independently transmitted to the electronic central unit 12 for pre-location for the selection step 108.
• an impact locating device such as one of those described above makes it possible to locate an impact using a reduced number N of transducers in an interactive surface whose dimensions can be enlarged by having an M> N number of transducers, M being as large as desired, without increasing the complexity of impact location calculations.
• This makes it possible to envisage playful or other applications of interaction with large impactile surfaces, in particular image (s) or video walls, exploiting the inexpensive technology of impact locations by analysis of differences in propagation time. progressive mechanical waves. This results in lower cost devices.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Acoustics & Sound (AREA)
• Human Computer Interaction (AREA)
• General Physics & Mathematics (AREA)
• Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
• Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)

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• 2016
  • 2016-10-10 FR FR1659741A patent/FR3057367B1/fr not_active Expired - Fee Related
• 2017
  • 2017-10-06 US US16/340,574 patent/US20190285389A1/en not_active Abandoned
  • 2017-10-06 WO PCT/FR2017/052744 patent/WO2018069608A1/fr not_active Ceased
  • 2017-10-06 EP EP17786987.2A patent/EP3523596A1/de not_active Withdrawn

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